You've taken a gamble here and will be learning on the job, best of luck to you, it will broaden your experience, and even if you have under priced it, I doubt you will lose more than a single day or do...
It's only labour afterall.
The forum is great for advice, but sometimes there can be so many conflicting opinions it can be hard to sort out which bit of advice is the most specific for your particular circumstances.
Be sure to let us all know how you get on with this job...
Ian